Circumference and center point marker



Dec. 27, 1949 I. N. OPRESCU 2,492,367

CIRCUMFERENCE AND CENTER POINT MARKER Filed May 24, 1946 FIG.|

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[/12 fl oreocur Patented Dec. 27, 1949 UNITED STATES PATENT 1 OFFICECIRCUMFERENCE AND CENTER rom'r MARKER 1 Claim. 1

This invention relates to a center point cylindrical punch, and moreparticularly to such a device adapted for scribing circles andindicating the center points thereof in relation to bores ofpredetermined diameters.

A primary object of this invention is the provision of an improveddevice including a plurality of interchangeable cylindrical punches,each provided with a cutting edge and each adapted for a bore of a givendiameter, each of which is provided with a centrally positioned apertureof identical diameter adapted to accommodate a center punch.

A further object of the invention is the provision of a tool of thischaracter adapted to simplify the work of tool makers, machinists andothers in accurately determining the outline diameter of and the exactcenter of circles to be drilled or otherwise machined.

Other objects of the invention will in part be obvious and in part bepointed out as the description of the invention proceeds, and shown inthe accompanying drawings, wherein there is disclosed a preferredembodiment of this inventive concept.

In the drawings:

Figure 1 is a vertical sectional view taken substantially through thecenter line of one form of cylindrical punch embodying features of theinstant invention'disclosing the center punch in association therewith.

Figure 2 is a view similar to Figure 1, but showing a different diameterof cylindrical punch and the center punch removed.

Figure 3 is a side elevational view of one form of cylindrical punchhaving the center punch associated therewith, shown in association witha piece of material to be marked through a bore of a diameter inconformity to the diameter of the cylindrical punch, the material inwhich the bore is formed being disclosed in section.

Similar reference characters refer to similar parts throughout theseveral views of the drawmgs.

Having reference now to Figure 1, there is generally indicated at H! acylindrical punch of any desired diameter, the lower portion of which isrecessed, as at H, the edges being beveled, as at l2, to provide acutting edge l3 for scribing the exterior diameter of a circle of theexact size of the punch. The punch I is provided at its center with anaccurately aligned bore [4 extending from the upper extremity thereofinto the recessed portion ll, within which is adapted to fit anelongated center punch l5 provided with a point It adapted to extend aslight distance below the plane of the cutting edge I3. The upperextremity of the pin 15 carries an enlarged head I! of relatively heavymaterial, adapted to overlie the corresponding end of an associatedcylindrical punch I0 and transmit the force of a hammer blow thereon tothe cylindrical punch and center punch simultaneously.

Figure 2 discloses a similar cylindrical punch 10 provided with a recessll' beveled, as at l2, to form a cutting edge I3, and being providedwith an internal bore I4. It is to be noted that the punch II) issubstantially identical to the punch In with the exception of itsexternal diameter. The diameter of the internal bore [4' issubstantially identical to the bore l4, and the length of punch III issubstantially the same as that of punch I0 so that either the punch IDor the punch It will accommodate the center punch Obviously, numerouscylindrical punches similar to the above two described may be made in avariety of diameters, and are adapted to be accommodated in bores l8formed in stock [9 of any suitable type, as disclosed in Figure 3, forthe purpose of scribing circles with the edges [3 and marking thecenters thereof with the point IS on any suitable material 20 to beworked.

From the foregoing the operation of the device should be readilyunderstandable. When it is desired to mark and center a circle in anydesired piece of material 28 through a bore It, a selected cylindricalpunch In is first inserted in the bore, whereupon the center punch ISwith its centering point It is inserted in the associated bore M to itsfull length, the point l6 extending a slight distance below the plane ofthe cutting edge l3. A relatively sharp blow with a hammer or similardevice on the head i! will cause the cutting edge I3 to scribe theexternal diameter of the circle to be cut, and will simultaneouslythrough the point It mark the exact center of the circle.

From the foregoing it will now be seen that there is herein provided adevice which accomplishes all the objects of this invention, and others,including many advantages of great practical utility and commercialimportance.

As many embodiments may be made of this inventive concept, and as manymodifications may be made in the embodiment hereinbefore shown anddescribed, it is to be understood that all matter herein is to beinterpreted merely as illustrative and not in a limiting sense.

movably positioned in the bore o..-sa:id-' cy'lindnie cal punch andhaving a pointed end substantially in the plane of the cutting edge ofsaid cylindrical punch end flange, and a head securedon the end of saidcenter punch 01mm the pointed end thereof and overlying thecorresponding end of said cylindrical punchvto transmit the force of ahammer blow on saidhead't'o 4 said cylindrical punch and said centerpunch simultaneously.

ILIE N. OPRESCU.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 306,413 McArdle Oct. 14, 1884724,759 Twambley Apr. '7, 1903 '-72A3,-036v McA-lpine Apr. 21, 1903766,677 Eagle Aug. 2, 1904 804,795 Cummings Nov. 14, 1905 824,867I-Ioughton July 3, 1906 1395;081 Brion Oct. 25, 1921

